This invention generally pertains to a method for etching silicon wafers with an etching solution consisting essentially of potassium hydroxide (KOH) and water (H.sub.2 O). Generally in (100) silicon etching using KOH, an anisotropic etching solution consisting of KOH, H.sub.2 O and an alcohol additive, usually isopropyl alcohol (IPA), is used. The particular etching solution etches only the (100) plane at an appreciable rate when applied to the (100) oriented plane. Because the (110) and (111) planes are not significantly affected in this process, the resulting etched cavity is V-shaped.
Generally, the etching process takes place in a temperature controlled pyrex container. When this pyrex is exposed to the KOH, certain complex silicates can be leached from the container. To counteract the possible contamination by these complex silicates, an alcohol additive is used. The alcohol additive, however, decreases the obtainable etch rate. Previous experimentation with a KOH and H.sub.2 O etching solution has been performed using a pyrex container. However, the inferior results obtained do not indicate that a KOH and H.sub.2 O only etching solution in a non-leachable container is a superior etching solution to one of KOH, H.sub.2 O and IPA. In an etching solution, the properties of high rate and quality are desired. Therefore, an optimum etching solution is one which will give a desired combination of etch rate and etch quality.